Electron microscopy situation in the diagnosis of minimal change disease; a 16-year survey

Abstract

Introduction: Minimal change disease (MCD) is one of the most common diseases affecting glomeruli and causing nephrotic syndrome in both adults and children. Objectives: The aim of this study was to evaluate the degree of accordance between light, fluorescent, and electron microscopies in the diagnosis of MCD. Patients and Methods: In this cross-sectional study, we investigated kidney biopsies which were sent to the referral electron microscopy unit (affiliated to Shiraz University of Medical Sciences) from 2001 to 2016. The final diagnosis of MCD was based on the electron microscopy (EM) study. For each patient, the primary light microscopy (LM) finding was compared with EM diagnosis. The available patients’ demographic, clinical, and paraclinical data were extracted. All the statistical analysis was performed in SPSS 19.0 and P<0.05 was considered as statistically significant. Results: Among all 2865 kidney biopsies, the data of 143 (5.0%) patients with approved MCD by EM were analyzed. The mean age of patients was 23.1± 17.4 years since most of them were male (54.9%). Normal blood urea nitrogen (BUN) and creatinine were observed in 76.6% and 78.6% of them respectively. Around, 140 (97.9%) of patients had no tubular atrophy and interstitial fibrosis. The role of EM in the diagnosis of MCD for 61 (50.0%) of cases were essential, for 61 (50.0%) cases were helpful while there was no case with the role of non-necessary. The immunofluorescence (IF) study was performed for 99 (69.2%) patients. Among them, it was negative for 60 (60.6%) of cases and was positive for IgM and C3 in 19 (19.2%) and 11 (11.1%) of cases respectively. The proportion of flank pain was significantly higher among adults. Conclusion: The importance of EM for the diagnosis of MCD is indispensable and undeniable; while LM is not capable of independently leading to a certain diagnosis of MCD. Considering the limitations of using EM, the results obtained from this study can help with the appropriate use of electron microscopy and help physicians to reach earlier diagnosed.